There have been many proposals for devices that seek to harness ocean wave energy, with some of the devices operating at the water surface and others under water.
Devices operating under water typically involve a moveable element such as a diaphragm adapted to deflect in response to wave action. An example of such a device is disclosed in WO 2004/003380. The device rests on the seabed and comprises a body structure having a diaphragm adapted to deflect in response to wave energy. A working chamber is disposed immediately below the diaphragm and contains a compressible fluid, conveniently air. The compressible fluid is under pressure to provide a lifting force to counter-balance the weight of the diaphragm and any attachments thereto, as well as the seawater above the diaphragm. The upper surface of the diaphragm is exposed to seawater. The diaphragm is operably connected to a reciprocating pump, whereby deflection of the diaphragm causes operation of the reciprocating pump.
With such an arrangement, it is necessary to provide a structure on the seabed, with the structure incorporating the diaphragm and a working chamber containing a compressible fluid below the diaphragm. Such a structure can be relatively expensive to construct and maintain.
It is against this background that the present invention has been developed.